Effect of Salt Stress on Photosynthetic and Antioxidant Characteristics in Purslane (Portulaca oleracea)

Purslane (Portulaca oleracea L.), a typical C-4 plant, has the characteristic of high saline-alkali tolerance and strong adaptability. With the wild purslane as materials, photosynthetic physiological characteristics of purslane were studied under the different concentrations of NaCl (0, 50, 150, 200 mmol.L-1). The results showed that with the increase of NaCl concentration, the intercellular CO2 concentration of purslane and the values of chlorophyll a/b increased, while transpiration rate, net photosynthesis rate, stomatal conductivity and chlorophyll contents decreased. The small reduction in photosynthetic capacity of purslane caused by 50 mmol.L-1 NaCl stress was considered having no big effect on the growth of the purslane. The proline and Malondialdehyde (MDA) contents and the activity of Peroxidase (POD) in leaves of purslane increased with the increase of salt concentrations. However, the activities of catalase (CAT) and superoxide dismutase (SOD) have a maximum under 50 mmol.L-1 NaCl concentrations. Purslane had stronger antioxidant capacities at 50 mmol.L-1 NaCl concentration. In brief, the high photosynthetic efficiency and antioxidant characteristics of purslane were adapted to salt stress, which could provide technical reference for further improving saline-alkali soil and developing salt-resistant plant germplasm resources. (C) 2020 Friends Science Publishers